1. Field of the Invention
The present invention relates to a method of forming a seal ring structure, and more particularly, to a method of forming a seal ring structure having a v-shaped dielectric layer conformally and totally overlapping a conductive layer, which may serve as a protective structure for an integrated circuit region.
2. Description of the Prior Art
In order to protect a region of a semiconductor device in which an integrated circuit is formed (hereinafter referred to as an “integrated circuit (IC) region”) from being affected by moisture and ions contained in an ambient air, a protective structure called a “seal ring”, “die edge seal”, or “guard ring” is provided on an inner side of a scribe line, that is, in the vicinity of an edge portion of a chip (die). In a high-productivity process, a typical seal ring is formed of interconnect layers and contacts made of materials in the same manner as the integrated circuit (IC) region of the semiconductor device, and surrounds the integrated circuit (IC) region.
As to the protective structure, a metal layer such as an aluminum metal layer can be additionally disposed on the interconnect layers to improve the strength of the protective structure. However, with the trend of miniaturization of the electronic products, as the metal layer is predetermined to fill an opening partially exposing the interconnect layers, the small critical dimension of the interconnect layers may shrink the size of the opening, and the overhang defect may be formed during the formation of the metal layer, which may damage the thickness uniformity of the film such as a redistribution layer (RDL) that is later formed on the overall wafer through sputtering process. Consequently, how to avoid the formation of the overhang defect in the metal layer of the protective structure is still an important issue in the field.